Japanese Patent Laying-Open Nos. 2004-343845 and 2001-119961 disclose techniques for reducing the drive device in size by housing a motor and an inverter in one case for integration in the drive device for a hybrid vehicle, as a kind of a vehicle drive device, provided with a motor as a vehicle driving power source.
However, the drive device for a hybrid vehicle disclosed in each of Japanese Patent Laying-Open Nos. 2004-343845 and 2001-119961 has a structure merely having an inverter mounted on a motor, which leaves room for improvement in the position of the center of gravity of the vehicle with respect to the height direction when the device is mounted on the vehicle. Furthermore, the saving of space for mounting the drive device for a hybrid vehicle is not sufficiently taken into consideration.
In order to allow the device to be mounted in various types of vehicles, it is desirable that the inverter and the motor can be arranged within the contour approximately equal to that of the automatic transmission disposed adjacent to the engine in the ordinary vehicle.
Furthermore, a vehicle equipped with a converter boosting the battery voltage for improving efficiency is recently developed. Japanese Patent Laying-Open Nos. 2004-343845 and 2001-119961 described above do not disclose the concept that the inverter and the motor are integrated in consideration of integration of the boost converter. The integration of the boost converter also requires consideration of the heat generated in the boost converter portion. Particularly, the reactor that is large in size as a component is required to be cooled in some way.
Furthermore, in the power semiconductor elements including a boost converter and an inverter, the heat amount differs in accordance with the difference in the power loss occurring at the time of the switching operation. Therefore, when the boost converter is integrated, it is necessary to ensure the coolness of the power semiconductor element along with the reactor as described above.
An object of the present invention is, in a vehicle drive device in which a rotating electrical machine and an electric circuit group (a converter, an inverter and the like) driving the rotating electrical machine are integrated, to ensure the coolness of the electric circuit group and also to reduce the device in size.